Patent US3787339A successfully refreshed from Google Patents.
US3787339A
Expired / Lapsed
US
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Process for defouling anion exchange resins with chlorine dioxide
Assignee: Veolia WTS Systems USA Inc
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Filing: 1972-09-07
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Granted: 1974-01-22
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Expires: 1992-09-07
Abstract
Abstract A process for treating fouled anion exchange resins with a stabilized chlorine dioxide solution for the purpose of regenerating the same for reuse. The process is especially useful for treating anion exchange membranes which have become fouled when employed in the electrodialysis of solutions containing large organic molecules.
Inventors
- 👤 R Hodgdon
- 👤 E Roach
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 06:07
CPC Classifications
B; B01; B01J; B01J49/00; B01J49/50; B01J49/57
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
21 words
The process of claim 1 wherein the period of contact time of the fouled resins is at least about 17 hours.
Claim 2
Dependent Claim
39 words
The process of claim 1 wherein the fouled ion exchange resin material is in a sheet or membrane form and the stabilized chlorine dioxide employed comprises a concentration of approximately 2.5 to 5 percent by weight of chlorine dioxide.
Claim 3
Dependent Claim
22 words
The process of claim 3 wherein the anion membrane after being contacted with said stabilized chlorine dioxide is further treated by acidification.
Claim 4
Dependent Claim
15 words
The process of claim 4 wherein the acidification is by contact with hydrochloric acid solution.
Claim 5
Dependent Claim
28 words
The process of claim 3 wherein the membrane after being contacted with stabilized chlorine dioxide is further treated with an aqueous solution of an alkali metal chloride salt.
Claim 6
Dependent Claim
11 words
The process of claim 6 wherein the salt is sodium chloride.
Claim 7
Dependent Claim
45 words
The process of regenerating fouled anion exchange resin comprising treating said fouled resin with an aqueous solution of chlorine dioxide, then treating with an aqueous solution of an acid and thereafter further treating the said resin with an aqueous solution of an alkali metal chloride.
Claim 8
Dependent Claim
19 words
The process of claim 8 wherein the acid is hydrochloric acid and the alkali metal chloride is sodium chloride.
References Cited (Backward Citations)
US3078224A
Cited
US3123553A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-21 | 1977-07-23 | 1978-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-21 | 1981-07-23 | 1982-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-21 | 1985-07-23 | 1986-01-22 | $7700.00 | Window Closed / Lapsed |